1. Field of the Invention
The present invention relates to cementitious compositions, and relates to the use of such compositions in corrosion protection.
2. The Prior Art
The present invention relates to cementitious compositions, and relates to the use of such compositions in corrosion protection.
The corrosion of metals in contact with water occurs by an aqueous electrochemical mechanism. This involves the presence of water containing dissolved ions at the metal surface, and the corresponding transfer of the electrons from the metal surface to the aqueous environment in contact with it. Corrosion protection involves interfering with these processes.
Current internal protection systems for water pipes usually consist of either cement mortars or epoxy resin polymeric coatings. Cement mortars suffer from a number of problems, such as lime leaching when placed in low alkalinity and low hardness waters. This results in impaired water quality by increasing the pH (ie the alkalinity) and calcium concentrations, and causes structural deterioration of the cement mortar, which results in poor durability. Epoxy resins can also suffer from a number of problems: if they are insufficiently cured, then there may be problems with water quality; there may be blistering; and there may be poor coverage at pipe joints.